← Rounding off and best estimate lesson New set →

Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 541 · 40 questions
TalentJR

How to do it in your head (Round, then work): Round each number: 2-digit numbers to the nearest ten, 3-digit numbers to the nearest hundred. Do the easy sum with the round numbers. Choose the option closest to your estimate.

NameDateTime takenScore ___ / 40
  1. 1.Best estimate of 168 + 358? (a) 600 (b) 800 (c) 400
  2. 2.Best estimate of 335 + 140? (a) 600 (b) 200 (c) 400
  3. 3.Best estimate of 17 × 92? (a) 18000 (b) 1800 (c) 180
  4. 4.Best estimate of 147 + 783? (a) 1100 (b) 900 (c) 700
  5. 5.Best estimate of 156 + 484? (a) 900 (b) 700 (c) 500
  6. 6.Best estimate of 26 × 90? (a) 27000 (b) 2700 (c) 270
  7. 7.Best estimate of 800 + 481? (a) 1100 (b) 1500 (c) 1300
  8. 8.Best estimate of 278 + 686? (a) 1000 (b) 800 (c) 1200
  9. 9.Best estimate of 24 × 82? (a) 160 (b) 1600 (c) 16000
  10. 10.Best estimate of 334 + 479? (a) 1000 (b) 800 (c) 600
  11. 11.Best estimate of 618 + 296? (a) 900 (b) 1100 (c) 700
  12. 12.Best estimate of 431 + 646? (a) 800 (b) 1200 (c) 1000
  13. 13.Best estimate of 29 × 67? (a) 2100 (b) 210 (c) 21000
  14. 14.Best estimate of 48 × 18? (a) 100 (b) 1000 (c) 10000
  15. 15.Best estimate of 256 + 656? (a) 1200 (b) 1000 (c) 800
  16. 16.Best estimate of 863 + 223? (a) 1300 (b) 1100 (c) 900
  17. 17.Best estimate of 502 + 162? (a) 700 (b) 500 (c) 900
  18. 18.Best estimate of 33 × 42? (a) 12000 (b) 1200 (c) 120
  19. 19.Best estimate of 60 × 60? (a) 36000 (b) 360 (c) 3600
  20. 20.Best estimate of 32 × 87? (a) 2700 (b) 27000 (c) 270
  21. 21.Best estimate of 464 + 247? (a) 700 (b) 900 (c) 500
  22. 22.Best estimate of 51 × 92? (a) 45000 (b) 4500 (c) 450
  23. 23.Best estimate of 56 × 93? (a) 540 (b) 54000 (c) 5400
  24. 24.Best estimate of 46 × 17? (a) 1000 (b) 100 (c) 10000
  25. 25.Best estimate of 606 + 305? (a) 1100 (b) 900 (c) 700
  26. 26.Best estimate of 495 + 554? (a) 1300 (b) 900 (c) 1100
  27. 27.Best estimate of 213 + 456? (a) 700 (b) 900 (c) 500
  28. 28.Best estimate of 718 + 652? (a) 1200 (b) 1600 (c) 1400
  29. 29.Best estimate of 98 × 39? (a) 4000 (b) 400 (c) 40000
  30. 30.Best estimate of 83 × 34? (a) 240 (b) 2400 (c) 24000
  31. 31.Best estimate of 604 + 126? (a) 900 (b) 500 (c) 700
  32. 32.Best estimate of 48 × 90? (a) 45000 (b) 4500 (c) 450
  33. 33.Best estimate of 30 × 56? (a) 18000 (b) 180 (c) 1800
  34. 34.Best estimate of 16 × 90? (a) 18000 (b) 180 (c) 1800
  35. 35.Best estimate of 13 × 16? (a) 2000 (b) 200 (c) 20
  36. 36.Best estimate of 42 × 34? (a) 1200 (b) 120 (c) 12000
  37. 37.Best estimate of 328 + 151? (a) 300 (b) 500 (c) 700
  38. 38.Best estimate of 708 + 322? (a) 1200 (b) 800 (c) 1000
  39. 39.Best estimate of 27 × 37? (a) 12000 (b) 1200 (c) 120
  40. 40.Best estimate of 52 × 96? (a) 5000 (b) 500 (c) 50000

Answer key

  1. 600
  2. 400
  3. 1800
  4. 900
  5. 700
  6. 2700
  7. 1300
  8. 1000
  9. 1600
  10. 800
  11. 900
  12. 1000
  13. 2100
  14. 1000
  15. 1000
  16. 1100
  17. 700
  18. 1200
  19. 3600
  20. 2700
  21. 700
  22. 4500
  23. 5400
  24. 1000
  25. 900
  26. 1100
  27. 700
  28. 1400
  29. 4000
  30. 2400
  31. 700
  32. 4500
  33. 1800
  34. 1800
  35. 200
  36. 1200
  37. 500
  38. 1000
  39. 1200
  40. 5000

Free mental maths lessons, practice and worksheets at talentjr.in/mental-maths